Influence of Radio Interference on the MSK Signals Demodulator

The work is devoted to communication systems. The systems under consideration are digital. The influence of radio interference on the communication channel using the minimum shift keying (MSK) signal is considered. The interest in MSK signals is due to their rather high spectral efficiency. The envelope of this signal is unchanged. The constancy of the envelope of these signals allows more efficient use of the transmitter power and the use of narrow-band selectors in the receiver. The influence of radio interference of the type: BPSK, QPSK, MSK and harmonic on the communication channel are considered. Unlike other works, the influence of radio interference is considered, the average frequencies (carriers) of which differ significantly from the average frequency of the useful signal. “Bit errors” occurring in radio interference conditions are considered. The study of the interference immunity of the communication channel was carried out using the demodulator MSK signal. The clock synchronization signal is allocated in it using phase automatic systems. The parameters of these systems are chosen so that the probability of interruption of tracking in them during the experiment is close to zero. This significantly reduces the likelihood of dragging out the time of the experiment. The experimental part of this work was done using Matlab software. It is shown that when the difference between the frequencies of the radio interference and the useful MSK of the radio signal exceeds the deviation of the frequency of the useful signal more then 3 times, the “bit errors” remains unacceptably large.